JP2007320001A - Method and apparatus for verifying annular reinforcement part formed in outer periphery of wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for easily verifying whether a width of an annular reinforcement part formed in a redundant outer periphery of a wafer is within an allowable range. <P>SOLUTION: The wafer 10 is provided with, on its front surface: a device domain with a plurality of devices formed; and a redundant periphery domain surrounding the device domain. The domain in the rear surface of the wafer 10, which corresponds to the device domain of the front surface, is formed to have a predetermined thickness by grinding. At the same time, the domain in the rear surface of the wafer 10, which corresponds to the redundant periphery domain of the front surface, remains and forms the annular reinforcement part 105b. The method includes verifying the width of the annular reinforcement part 105b. Verification whether the width of the annular reinforcement part 105b is within the allowable range is performed by checking an image of the annular reinforcement part 105b taken by imaging means 11 at every predetermined angle of rotation of a supporting table 91 which is designed to support the front surface of the wafer 10 and rotate it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a predetermined thickness by grinding the device region on the back surface of a wafer having a device region having a plurality of devices formed on the surface and an outer peripheral surplus region surrounding the device region. The present invention relates to a method and a confirmation device for confirming the width dimension of an annular reinforcing portion formed by leaving a region corresponding to the outer peripheral surplus region on the back surface.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual semiconductor chips. In addition, optical device wafers with gallium nitride compound semiconductors laminated on the surface of a sapphire substrate are also divided into individual optical devices such as light emitting diodes and laser diodes by cutting along the streets, and are widely used in electrical equipment. ing.

As described above, the wafer to be divided is formed to have a predetermined thickness by grinding or etching the back surface before cutting along the street. In recent years, it has been required to form a wafer with a thickness of 50 μm or less in order to reduce the weight and size of electrical equipment.
However, if the thickness of the wafer is formed to be 50 μm or less, the wafer tends to be damaged, and there is a problem that handling such as transport of the wafer becomes difficult.

  In order to solve the above-mentioned problem, the applicant grinds the region corresponding to the device region on the back surface of the wafer to form the thickness of the device region to a predetermined thickness, and leaves the outer peripheral surplus region on the back surface of the wafer. Japanese Patent Application No. 2005-165395 proposed a wafer processing method that facilitates handling of thinned wafers by forming an annular reinforcing portion.

  Thus, since the width of the outer peripheral area of the wafer is as narrow as about 2 mm from the outer peripheral edge, the center of rotation of the chuck table that holds the wafer when the area corresponding to the device area on the back surface of the wafer is ground by the grinding device. If the center of the wafer does not match the center of the wafer, an annular reinforcing portion having a uniform width cannot be formed. If the annular reinforcing portion formed in the outer peripheral area of the wafer is not uniform in width, there is a problem that the thickness of the device region is not ground to a predetermined thickness in the region where the width of the annular reinforcing portion is large. Therefore, it is desirable to be able to confirm whether or not the width of the annular reinforcing portion is formed within an allowable range.

  The present invention has been made in view of the above facts, and the main technical problem thereof is to easily confirm whether or not the width of the annular reinforcing portion formed in the outer peripheral surplus region of the wafer is within an allowable range. It is providing the confirmation method and confirmation apparatus of the annular reinforcement part formed in the outer peripheral part which can do.

In order to solve the above-mentioned main technical problem, according to the present invention, it corresponds to the device region on the back surface of a wafer provided with a device region having a plurality of devices formed on the surface and an outer peripheral surplus region surrounding the device region. The region is ground to form a predetermined thickness, and the region corresponding to the outer peripheral surplus region on the back surface of the wafer is formed on the outer peripheral portion of the wafer to confirm the width dimension of the annular reinforcing portion formed. A method for confirming the annular reinforcing portion,
The front surface side of the wafer having an annular reinforcing portion formed on the back surface is held by a holding table configured to be rotatable, and the annular reinforcing portion is imaged by the imaging means each time the holding table is rotated by a predetermined angle. Check whether there is a region where the width of the reinforcing part is larger than the allowable range,
A method for confirming the annular reinforcing portion formed on the outer peripheral portion of the wafer is provided.

Further, according to the present invention, a region corresponding to the device region on the back surface of the wafer having a device region having a plurality of devices formed on the surface and an outer peripheral surplus region surrounding the device region is ground to a predetermined thickness. And confirming the width dimension of the annular reinforcing portion formed by leaving a region corresponding to the outer peripheral surplus region on the back surface of the wafer, and a confirmation device for the annular reinforcing portion formed on the outer peripheral portion of the wafer. ,
A holding table configured to hold and rotate the wafer, and a holding table mechanism including table position detecting means for detecting a rotation position of the holding table;
Imaging means for imaging the outer peripheral area of the wafer held by the holding table;
Control means for determining the width dimension of the annular reinforcing portion formed in the outer peripheral area of the wafer based on the image information imaged by the imaging means, and determining whether or not there is an area where the width dimension is larger than the allowable range And has,
An apparatus for confirming an annular reinforcing portion formed on the outer peripheral portion of a wafer is provided.

  According to the present invention, since it is possible to confirm whether or not there is a region where the width of the annular reinforcing portion formed on the outer peripheral portion of the wafer is larger than the allowable range, the width dimension of the annular reinforcing portion is within the allowable range. If a larger area exists, a part of the device area is not formed to a predetermined thickness, so that it can be determined as a defective product, and can be ground and corrected again. Therefore, the generation of defective devices can be prevented.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a confirmation method and a confirmation device for an annular reinforcing portion formed on the outer peripheral portion of a wafer according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a grinding apparatus equipped with a confirmation device for an annular reinforcing portion formed on the outer peripheral portion of a wafer constructed according to the present invention.
The grinding device in the illustrated embodiment includes a device housing 2 having a substantially rectangular parallelepiped shape. A stationary support plate 21 is erected on the upper right end of the device housing 2 in FIG. Two pairs of guide rails 22, 22 and 23, 23 extending in the vertical direction are provided on the inner surface of the stationary support plate 21. A rough grinding unit 3 as rough grinding means is mounted on one guide rail 22, 22 so as to be movable in the vertical direction, and a finish grinding unit 4 as finish grinding means is vertically installed on the other guide rail 23, 23. It is mounted to move in the direction.

  The rough grinding unit 3 includes a unit housing 31, a grinding wheel 33 attached to a wheel mount 32 rotatably attached to the lower end of the unit housing 31, and a wheel mount 32 attached to the upper end of the unit housing 31 with an arrow. An electric motor 34 that rotates in the direction indicated by 32a and a moving base 35 on which the unit housing 31 is mounted are provided. The grinding wheel 33 includes an annular grindstone base 331 and a rough grinding grindstone 332 mounted on the lower surface of the grindstone base 331. Guided rails 351 and 351 are provided on the moving base 35, and the guided rails 351 and 351 are movably fitted to the guide rails 22 and 22 provided on the stationary support plate 21. The rough grinding unit 3 is supported so as to be movable in the vertical direction. The rough grinding unit 3 in the form shown in the figure includes a grinding feed mechanism 36 that moves the moving base 35 along the guide rails 22 and 22 and feeds the grinding wheel 33 by grinding. The grinding feed mechanism 36 includes a male screw rod 361 that is disposed on the stationary support plate 21 in a vertical direction parallel to the guide rails 22 and 22 and is rotatably supported, and a pulse motor 362 for rotationally driving the male screw rod 361. And a female screw block (not shown) that is mounted on the moving base 35 and is screwed with the male screw rod 361. By driving the male screw rod 361 forward and reverse by a pulse motor 362, the rough grinding unit 3 is moved up and down. It is moved in the direction (direction perpendicular to the holding surface of the chuck table described later).

  The finish grinding unit 4 is also configured in the same manner as the rough grinding unit 3, and includes a unit housing 41, a grinding wheel 43 attached to a wheel mount 42 rotatably attached to a lower end of the unit housing 41, and the unit. An electric motor 44 that is mounted on the upper end of the housing 41 and rotates the wheel mount 42 in the direction indicated by the arrow 42a, and a moving base 45 on which the unit housing 41 is mounted are provided. The grinding wheel 43 includes an annular grinding wheel base 431 and a grinding wheel 432 for finish grinding mounted on the lower surface of the grinding wheel base 431.

  Guided rails 451 and 451 are provided on the moving base 45, and the guided rails 451 and 451 are movably fitted to the guide rails 23 and 23 provided on the stationary support plate 21. The finish grinding unit 4 is supported so as to be movable in the vertical direction. The finish grinding unit 4 in the illustrated form includes a grinding feed mechanism 46 that moves the moving base 45 along the guide rails 23 and 23 and feeds the grinding wheel 43 by grinding. The grinding feed mechanism 46 includes a male screw rod 461 that is disposed on the stationary support plate 21 in a vertical direction parallel to the guide rails 23 and 23 and is rotatably supported, and a pulse motor for driving the male screw rod 461 to rotate. 462 and a female screw block (not shown) that is mounted on the moving base 465 and screwed with the male screw rod 461. By driving the male screw rod 461 forward and backward by a pulse motor 462, the finish grinding unit 4 is moved up and down. It is moved in the direction (direction perpendicular to the holding surface of the chuck table described later).

  The grinding apparatus in the illustrated embodiment includes a turntable 5 disposed so as to be substantially flush with the upper surface of the apparatus housing 2 on the front side of the stationary support plate 21. The turntable 5 is formed in a relatively large-diameter disk shape, and is appropriately rotated in a direction indicated by an arrow 5a by a rotation driving mechanism (not shown). In the illustrated embodiment, three chuck tables 6 are arranged on the turntable 5 so as to be rotatable in a horizontal plane with a phase angle of 120 degrees. The chuck table 6 includes a disk-shaped base 61 and a suction holding chuck 62 formed in a disk shape by a porous ceramic material, and a wafer placed on the suction holding chuck 62 (holding surface) is not shown. Suction is held by operating the suction means. The chuck table 6 configured as described above is rotated in a direction indicated by an arrow 6a by a rotation driving mechanism (not shown) as shown in FIG. The three chuck tables 6 arranged on the turntable 5 have a wafer carry-in / out area A, a rough grinding area B, a finish grinding area C, and a wafer carry-in / out area when the turntable 5 is appropriately rotated. A is moved sequentially to A.

  The illustrated grinding apparatus is disposed on one side with respect to the wafer loading / unloading area A, and is disposed on the other side with respect to the wafer loading / unloading area A. The first cassette 7 stocks the wafer before grinding. And a second cassette 8 for stocking the wafer after grinding, and a holder placed between the first cassette 7 and the wafer loading / unloading area A for placing the wafer unloaded from the first cassette 7. Arranged between the table mechanism 9, the image pickup means 11 for imaging the wafer disposed above the holding table mechanism 9 and held by the holding table mechanism 9, and the wafer loading / unloading area A and the second cassette 8. The spinner cleaning means 12 and the wafer housed in the first cassette 7 are carried out to the holding table mechanism 9 and the wafer cleaned by the spinner cleaning means 12 is stored in the second cassette 8. Wafer carrying means 13 for feeding, wafer carrying means 14 for carrying the wafer placed on the holding table 9 onto the chuck table 6 positioned in the wafer carry-in / out area A, and positioned in the wafer carry-in / out area A Wafer unloading means 15 for conveying the wafer after grinding mounted on the chuck table 6 to the cleaning means 12 is provided.

  The first cassette 7 accommodates the semiconductor wafer shown in FIG. The semiconductor wafer 10 shown in FIG. 2 is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of streets 101 are formed in a lattice shape on the surface 10a, and a plurality of streets partitioned by the plurality of streets 101 are formed. A device 102 such as an IC or LSI is formed in the region. The semiconductor wafer 10 configured as described above includes a device region 104 in which the device 102 is formed and an outer peripheral surplus region 105 surrounding the device region 104. The width of the outer peripheral surplus region 105 is set to 2 to 3 mm. A plurality of semiconductor wafers 10 configured as described above are accommodated in the first cassette 7 with the protective member 100 adhered to the surface 10a as shown in FIG. At this time, the semiconductor wafer 10 is accommodated with the back surface 10b facing upward.

  As shown in FIG. 4, the holding table mechanism 9 includes a holding table 91 whose upper surface functions as a holding surface 91a, a rotating shaft 92 provided at the center of the lower surface of the holding table 91, and a pulse for rotating the rotating shaft 92. The drive shaft 931 and the rotating shaft 92 of the pulse motor 93 are transmission-coupled. The holding table 91 is provided with a suction hole 911 that opens in the holding surface 91a, and the suction hole 911 communicates with a suction means (not shown). The drive shaft 931 of the pulse motor 93 constituting the holding table mechanism 9 is equipped with a rotary encoder 94 as table position detecting means for detecting the rotation position of the holding table 91. The rotary encoder 94 detects the detection signal. Is sent to the control means 200.

  The imaging means 11 is attached to a support member 110 disposed adjacent to the holding table mechanism 9 as shown in FIG. The imaging unit 11 includes an illuminating unit that illuminates a workpiece, an optical system that captures an area illuminated by the illuminating unit, an imaging device (CCD) that captures an image captured by the optical system, and the like. The outer peripheral part of the wafer placed on the holding surface 91a of the holding table 91 is imaged. The imaging unit 11 configured as described above sends image information captured as shown in FIG. 4 to the control unit 200.

  Continuing the description with reference to FIG. 4, the control means 200 has a width of an annular reinforcing portion formed on the outer peripheral portion of the wafer as will be described later based on detection signals from the imaging means 11 and the rotary encoder 94. Confirmation control is performed to determine whether or not it is within the allowable range. The control means 200 includes a pulse motor 93 of the holding table mechanism 9, a spinner cleaning means 12, a wafer transport means 13, a wafer carry-out means 15, a rough grinding unit 3, a wafer carry-in means 14, a finish grinding unit 4, and a turntable 5. The chuck table 6 and the like are controlled, and the confirmation result is displayed on the display means 16.

The grinding apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
The pre-grinding semiconductor wafer 10 accommodated in the first cassette 7 is placed on the holding surface 91a of the holding table 91 that constitutes the holding table mechanism 9 by the vertical movement and forward / backward movement of the wafer transport means 13. Next, the wafer carry-in means 14 is operated to hold the semiconductor wafer 10 placed on the holding surface 91a of the holding table 9, and on the chuck holding chuck 62 of the chuck table 6 positioned in the wafer carry-in / out area A. Placed on. Then, the semiconductor wafer 10 is sucked and held on the chuck table 6 by operating a suction means (not shown).

  As described above, when the semiconductor wafer 10 is sucked and held on the upper surface (holding surface) of the chuck table 6 positioned in the wafer loading / unloading area A, the direction indicated by the arrow 5a by the rotary drive mechanism (not shown). Then, the chuck table 6 on which the semiconductor wafer 10 is placed is positioned in the rough grinding area B. Here, the relationship between the semiconductor wafer 10 held on the chuck table 6 and the grinding wheel 332 for rough grinding constituting the grinding wheel 33 will be described with reference to FIG. The rotation center P4 of the chuck table 6 and the rotation center P5 of the grinding wheel 332 are eccentric, and the outer diameter of the grinding wheel 332 is smaller than the diameter of the boundary line 106 between the device region 104 and the surplus region 105 of the semiconductor wafer 10. The size is set to be larger than the radius of the boundary line 106, and the annular grinding wheel 332 passes through the rotation center P 4 of the chuck table 6 (center P 2 of the semiconductor wafer 10).

  Next, as shown in FIG. 5, while rotating the chuck table 6 in the direction indicated by the arrow 6a at 300 rpm, the grinding wheel 332 is rotated in the direction indicated by the arrow 32a at 6000 rpm, and the grinding feed mechanism 36 is operated to perform grinding. The grinding wheel 332 of the wheel 33 is brought into contact with the back surface of the semiconductor wafer 10. Then, the grinding wheel 33 is ground and fed downward by a predetermined amount at a predetermined grinding feed speed. As a result, a region corresponding to the device region 104 is roughly ground and removed on the back surface of the semiconductor wafer 10 to form a circular recess 104b slightly thicker than a predetermined thickness (for example, 30 μm) as shown in FIG. At the same time, a region corresponding to the outer peripheral surplus region 105 is left and formed in the annular reinforcing portion 105b (concave rough grinding step).

  During this time, on the next chuck table 6 positioned in the wafer loading / unloading area A, the semiconductor wafer 10 before grinding is placed with its center aligned as described above. Then, the semiconductor wafer 10 is sucked and held on the chuck table 6 by operating a suction means (not shown). Next, the turntable 5 is rotated 120 degrees in the direction indicated by the arrow 5a, the chuck table 6 holding the semiconductor wafer 10 subjected to rough grinding is positioned in the finish grinding area C, and the semiconductor before grinding is processed. The chuck table 6 holding the wafer 10 is positioned in the rough grinding area B.

  In this way, the rough grinding unit 3 performs the above rough grinding on the back surface 10b of the semiconductor wafer 10 before the rough grinding held on the chuck table 6 positioned in the rough grinding region B, and finishes. A finish grinding unit 4 performs finish grinding on the back surface 10b of the semiconductor wafer 10 placed on the chuck table 6 positioned in the grinding zone C and subjected to rough grinding.

Here, the finish grinding will be described with reference to FIG.
The outer diameter of the grinding wheel 432 for finish grinding is the same as that of the grinding wheel 332 for rough grinding. Then, as shown in FIG. 7, the grinding wheel 432 for finish grinding is positioned so as to pass through the rotation center P4 of the chuck table 6 (center P2 of the semiconductor wafer 10). At this time, the outer peripheral edge of the grinding wheel 432 is positioned so as to contact the inner peripheral surface of the annular reinforcing portion 105b formed by the rough grinding process.

  Next, as shown in FIG. 7, while rotating the chuck table 6 in the direction indicated by the arrow 6a at 300 rpm, the grinding wheel 432 for finish grinding is rotated in the direction indicated by the arrow 42a at 6000 rpm, and the grinding feed mechanism 46 is rotated. By operating, the grinding wheel 432 of the grinding wheel 43 is brought into contact with the bottom surface of the circular recess 104b formed on the back surface of the semiconductor wafer 10. Then, the grinding wheel 43 is ground and fed downward by a predetermined amount at a predetermined grinding feed speed. As a result, the bottom surface of the circular recess 104b formed on the back surface of the semiconductor wafer 10 is finish-ground, and the region corresponding to the device region 104 is formed to a predetermined thickness (for example, 30 μm) (recess finish grinding step).

  As described above, the chuck table 6 holding the semiconductor wafer 10 that has been subjected to rough grinding in the rough grinding region B receives the semiconductor wafer 10 before grinding in the finish grinding region C and the workpiece loading / unloading region A. The held chuck table 6 is moved to the rough grinding area B, respectively. The chuck table 6 that has returned to the workpiece loading / unloading zone A via the rough grinding zone B and the finish grinding zone C releases the suction holding of the semiconductor wafer 10 that has been ground here. Then, the finish-ground semiconductor wafer 10 on the chuck table 6 positioned in the workpiece carry-in / carry-out area A is carried out by the workpiece carry-out means 15 to the cleaning means 12. The semiconductor wafer 10 transported to the cleaning means 12 is spin-dried while the grinding debris adhering to the back surface 10a (grinding surface) and the side surface is cleaned and removed here.

  The semiconductor wafer 10 cleaned and dried by the cleaning means 12 is used to check whether the width dimension of the annular reinforcing portion 105b formed by grinding as described above is within an allowable range. Is conveyed to a holding table 91 constituting the. In other words, the workpiece conveying means 13 is operated to place the semiconductor wafer 10 cleaned and dried by the cleaning means 12 on the holding surface 91 a of the holding table 9 constituting the holding table mechanism 9. Then, a suction means (not shown) is operated to suck and hold the semiconductor wafer 10 on the holding surface 91 a of the holding table 91.

  If the semiconductor wafer 10 is sucked and held on the holding surface 91a of the holding table 91 that constitutes the holding table mechanism 9, the imaging means 11 is operated to hold the outer periphery of the semiconductor wafer 10 while taking an image as shown in FIG. The pulse motor 93 constituting the table mechanism 9 is rotated in the direction indicated by the arrow 9a in FIG. Then, the imaging unit 11 captures an image every time the holding table 91 rotates by a predetermined rotation angle, and sends the image information to the control unit 200 (imaging process). This imaging step is performed while the holding table 91 is rotated once. At this time, it is desirable that the imaging means 11 is attached with a mask 110 having a thin slit 111 for imaging.

  Based on the image information sent from the image pickup means 11, the control means 200 detects the width dimension D of each image pickup position of the annular reinforcing portion 105 b formed on the outer peripheral portion of the semiconductor wafer 10. This width dimension D can be obtained from the number of pixels located in the annular reinforcing portion 105b in the slit 111a formed in the mask 111 in the image information sent from the imaging means 11. In this way, if the width dimension D of the annular reinforcing portion 105b is detected, the control means 200 checks whether or not there is a region where the width dimension D is larger than the allowable range. Then, the control means 200 determines that the semiconductor wafer 10 on which the annular reinforcing portion 105b is formed is a non-defective product if the width dimension D of each imaging position of the annular reinforcing portion 105b is all within the allowable range. The result is displayed on the display means 16. On the other hand, if there is a region where the width dimension D of the annular reinforcing portion 105b is larger than the allowable range, the control unit 200 determines that the product is defective and displays the determination result on the display unit 16. As described above, the holding table mechanism 9, the imaging means 11, and the control means 200 function as a confirmation device for confirming the width dimension of the annular reinforcing portion formed on the outer peripheral portion on the back surface of the wafer.

  As described above, if the quality of the semiconductor wafer 10 on which the annular reinforcing portion 105 b is formed is confirmed, the semiconductor wafer 10 is transported and stored in the second cassette 8 by the workpiece transport means 13.

  As described above, the region corresponding to the device region 104 on the back surface of the semiconductor wafer 10 is ground to form the circular recess 104b, and the region corresponding to the outer peripheral surplus region 105 is left so as to leave the annular reinforcing portion. When 105b is formed, when the width dimension D of the annular reinforcing portion 105b is outside the allowable range, a region larger than the allowable range and a region smaller than the allowable range exist with a phase of 180 degrees. In the region where the width dimension D of the annular reinforcing portion 105b is smaller than the allowable range, the device region 104 is formed to have a predetermined thickness, while the region where the width dimension D of the annular reinforcing portion 105b is larger than the allowable range is the device region 104. Is not formed to a predetermined thickness. Therefore, the semiconductor wafer 10 determined to be defective is corrected by performing the above-described grinding operation. As a result, it is possible to prevent the occurrence of defective devices.

The perspective view of the grinding device equipped with the confirmation apparatus of the cyclic | annular reinforcement part formed in the outer peripheral part of the wafer comprised according to this invention. 1 is a perspective view of a semiconductor wafer processed by the grinding apparatus shown in FIG. FIG. 3 is a perspective view showing a state where a protective member is attached to the surface of the semiconductor wafer shown in FIG. 2. The block diagram of the confirmation apparatus of the cyclic | annular reinforcement part formed in the outer peripheral part of the wafer with which the grinding apparatus shown in FIG. 1 is equipped. Explanatory drawing which shows the recessed part rough grinding process implemented by the grinding apparatus shown in FIG. FIG. 7 is an enlarged cross-sectional view of a semiconductor wafer that has been subjected to the rough concave grinding step shown in FIG. 6. Explanatory drawing which shows the recessed part finish grinding process implemented by the grinding apparatus shown in FIG. Explanatory drawing of the imaging process implemented by the grinding apparatus shown in FIG.

Explanation of symbols

2: device housing 3: rough grinding unit 33: grinding wheel 332: grinding wheel 4: finish grinding unit 43: grinding wheel 432: grinding wheel 5: turntable 6: chuck table 7: first cassette 8: second cassette 9: Holding table mechanism 91: Holding table 93: Pulse motor 94: Rotary encoder 10: Semiconductor wafer 11: Imaging means 12: Cleaning means 13: Wafer conveying means 14: Wafer carrying means 200: Control means

Claims (2)

A region corresponding to the device region on the back surface of the wafer having a device region having a plurality of devices formed on the front surface and an outer peripheral surplus region surrounding the device region is ground to a predetermined thickness. A method for confirming the annular reinforcing portion formed on the outer peripheral portion of the wafer for confirming the width dimension of the annular reinforcing portion formed by remaining the region corresponding to the outer peripheral surplus region on the back surface,
The front side of the wafer having an annular reinforcing portion formed on the back surface is held by a holding table configured to be rotatable, and the annular reinforcing portion is imaged by an imaging unit every time the holding table is rotated by a predetermined angle. Check whether the width of the annular reinforcing part is formed within the allowable range,
A method for confirming the annular reinforcing portion formed on the outer peripheral portion of the wafer. A region corresponding to the device region on the back surface of the wafer having a device region having a plurality of devices formed on the front surface and an outer peripheral surplus region surrounding the device region is ground to a predetermined thickness. In the confirmation device for the annular reinforcing portion formed on the outer peripheral portion of the wafer for confirming the width dimension of the annular reinforcing portion formed by remaining the region corresponding to the outer peripheral surplus region on the back surface,
A holding table configured to hold a wafer and be configured to be rotatable, and a holding table mechanism including a table position detecting unit that detects a rotation position of the holding table;
Imaging means for imaging the outer peripheral area of the wafer held by the holding table;
Control means for determining the width dimension of the annular reinforcing portion formed in the outer peripheral area of the wafer based on the image information imaged by the imaging means, and determining whether the width dimension is within an allowable range; Yes,
An apparatus for confirming an annular reinforcing portion formed on the outer peripheral portion of a wafer.

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